Various screw operated applicators are known in the art as described for example in U.S. Pat. No. 3,917,417. They are useful for dispensing such products as lip balms, deodorants, lubricants and the like.
In a typical stick applicator, the product to be dispensed sits within a tubular body of cylindrical or other shape. The product is supported in the body by a follower-plate or elevator which travels inside the body along the body's length. This follower plate or elevator is threadably engaged with a shaft of a dispensing screw having a handgrip member abutting the tubular body. The threaded shaft runs inside the body along the body's length. The follower plate or elevator moves in response to turning of the handgrip member.
In operation of the above described applicator, a user turns the handgrip member causing the threaded shaft of the screw to turn, and thereby cause the follower plate or elevator to travel inside the tubular body with concomitant movement of the product up or down from the dispensing opening in the body. The amount of product dispensed from or retracted into the body is proportionate to the extent to which the handgrip member is turned.
Deficiencies in existing stick applicators make them less than optimal in use. First, the amount of product dispensed is difficult to control because it is indiscriminately dispensed when the handgrip member is turned. Special care and attention are required to position the handgrip member so that a precise desired amount of product is exposed or dispensed. If too much of the product is extended, the stick can break. If too little is extended, inadequate application of the product results or repeated application is required. Second, accidental dispensing can be a problem with existing stick applicators. Since there is no stop or check on the handgrip member, it is easily turned by various types of unintended contact.
While other stick applicator structures are known which provide for incremental disposing, such structures are complex requiring multiple components of interrelating structures. This is expensive in terms of materials, time, and labor in assembly during the manufacturing process. For example, U.S. Pat. No. 1,950,324 describes a lipstick holder structured for clicking in incremental fashion for dispensing lipstick from the holder. FIGS. 1-3 of the patent illustrate a first embodiment using a plate with projections in conjunction with recesses formed in a base which in turn operate in conjunction with a turning means. In a second embodiment of FIGS. 4 and 5, corrugations and a pin structure are utilized rather than projections and recesses. This type of structure requires multiple interacting components. Cost in terms of materials, manufacturing time and assembly is a major consideration.
It would be advantageous to have a screw operated stick applicator that avoids accidental dispensing of product and that allows a user to quickly and easily dispense convenient predetermined amounts of product incrementally and without resorting to careful fine tuning of the handgrip member, in particular which does not require complex and expensive dispensing structures.